CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 869,191	$ 397,664
Short-term investments	1,245,782	1,494,711
Contracts receivable	61,896	76,204
Inventories	24,806	21,965
Other current assets	143,374	140,163
Total current assets	2,345,049	2,130,707
Property, plant and equipment, net	178,069	181,077
Patents, net	29,005	27,937
Deposits and other assets	59,567	50,034
Total assets	2,611,690	2,389,755
Current liabilities:
Accounts payable	11,904	17,199
Accrued compensation	38,810	65,728
Accrued liabilities	88,560	90,161
Income taxes payable	36	1,324
1 percent convertible senior notes, net	0	308,809
Current portion of long-term obligations	3,526	7,301
Current portion of deferred contract revenue	97,714	108,376
Total current liabilities	240,550	598,898
Long-term deferred contract revenue	351,879	424,046
Long-term obligations, less current portion	26,378	23,409
Long-term mortgage debt	59,713	59,984
Total liabilities	1,839,953	1,646,473
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 141,210,015 and 140,365,594 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively	141	140
Additional paid-in capital	1,964,167	1,895,519
Accumulated other comprehensive loss	(32,668)	(21,071)
Accumulated deficit	(1,159,903)	(1,131,306)
Total stockholders' equity	771,737	743,282
Total liabilities and stockholders' equity	2,611,690	2,389,755
0 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	619,119	0
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	$ 542,314	$ 540,136